During June 2025, Poperigby focused on maintaining and improving the NixOS/nix repository by addressing deprecation issues in Docker configuration. They delivered a targeted fix that replaced the deprecated mapAttrsFlatten function with mapAttrsToList in docker.nix, aligning the codebase with current Nix language standards and reducing future compatibility risks. Their work included a minor code refactor to enhance maintainability and code health, ensuring the configuration remains robust as Nix evolves. Utilizing their expertise in code refactoring and the Nix language, Poperigby’s contribution provided clear traceability and helped streamline ongoing maintenance for Docker-related Nix configurations within the repository.